Cost of servicing abroad v UK??

My neighbour has his Renault Scenic serviced in Calais, but he works for Euro Tunnel and gets crossings for £1. I know the service cost is cheaper, however if it saves enough £ to warrant the effort (and cost of a normal crossing) I'm not sure.

I used to go over to Calais before work to pick up beer and fuel every other month, a return trip on Euro Tunnel used to be £9 that early in the morning, but since the new management has come in all cheap crossings are gone. Also now I have a petrol and not a diesel, although the cost of diesel in France has gone up alot recently.

Kev.